Are you happy with your sleep?

What does sleep hygiene really mean?

Gary Burke – B.Sc, M.Sc, SENr

36% of UK adults struggle to get to sleep on a weekly basis, while almost 1 in 5 have trouble falling asleep every single night. Everyone has experienced it at some stage of their life – a poor night’s sleep will more than likely leave you less productive, reduce the quality of your work and put you in a worse mood overall. 

Some of you may be familiar with the term ‘sleep hygiene’ – it refers to habits & practices that can be used to help improve the quality of your sleep. Sleep hygiene isn’t all about giving yourself a caffeine curfew or what you do in the lead up to bedtime. Various other factors can contribute to a better sleep and I hope to shed some light on these below. 

Consistency

It’s been shown that having a consistent sleep schedule is more important than how long you sleep for (within reason). Having a set wake & sleep time each day (and not deviating from this by too much at the weekends) will help you fall asleep faster, improve the quality of your sleep, and help you feel less groggy in the mornings. 7-9 hours is best but if your schedule means you can’t manage that much, try to at least make it consistent.

Light

You may already know that screens can negatively affect your sleep through both the light of the screens and stimulation from what’s on the screen. It’s best to put the screens away in the hour leading up the bedtime if you want to optimise your sleep and minimise your morning grogginess. Reading a book or meditating before bed have both been shown to make it easier to fall asleep & improve quality of your sleep.

It’s best to avoid all bright light sources in the hours leading up to bedtime, not just blue light from screens. Bright light exposure late in the day suppresses your body’s production of melatonin – a hormone that makes us feel sleepy – making it more difficult to fall asleep and reducing the quality of your sleep when you finally doze off. 

In the mornings, it’s best to do the opposite: exposing yourself to bright light as soon as you wake (and over the first 2 hours of wakefulness) will both speed up the waking process by increasing alertness and make it easier to fall asleep that night. The sun is best – it’s much more intense that any artificial light source you’ll find have. The sun can be up to 400 times brighter than the average lightbulb! 

Temperature

Your body temperature has a natural cycle correlating with your body clock, peaking just before noon and falling again from late evening until it reaches its lowest point a couple hours before you wake up. You can adjust your body clock by facilitating a rise or a fall in body temperature, depending on the time of day.

Aligning your body clock & sleep/wake cycle is very important for getting good quality, replenishing sleep – incongruency between the two is a major reason why you may struggle to get to sleep at night and wake up feeling groggy and unrested.

Activities that lead to a drop in body temperature in the hour or two before bed will help – something that warms your body like light exercise or showering/bathing will lead to a subsequent drop in body temperature that coincides with your body’s daily temperature cycle, naturally making you sleepy. This is why keeping your bedroom at a cool temperature is important for getting a good night’s sleep.

In the morning, the opposite is true – practices that lead to an increase in body temperature can actually help you get to sleep faster that night. Cold showers – as well as being shown to increase productivity by improving dopamine levels – can help adjust your body clock so that you start to naturally feel sleepy at your usual bedtime. 

Exercise 

Exercising early in your day adjusts your body clock slightly earlier, making you naturally want to sleep earlier that night and makes your body more likely to wake up naturally around the time your alarm usually goes off. Some people often feel sluggish exercising early in the day – if you can manage to schedule some exercise in regularly, your body will adapt to make it feel easier.

Take-Home Points to Improve Sleep

  • Have a consistent sleep schedule, even over the weekend if possible
  • Avoid bright lights & screens in the hour before bed
  • Read a book or meditate before bed 
  • Light exercise or warm/hot showers close to bedtime
  • Exercise or cold showers in the morning make it easier to fall asleep that night

Glaister & Gissane, 2018.

doi: 10.1123/ijspp.2017-0312.

It is widely acknowledged that caffeine is the most consumed drug or psychoactive substance throughout the globe, mainly via the medium of coffee, the world’s most popular beverage, with north of a billion cups being sold daily, in saying this, in recent years the way in which caffeine is consumed has changed with the development of pre workout formulas & energy drinks. Much research has been done into the topic of just how caffeine impacts sports performance, and what we know for sure is that it has a net positive impact, exactly how this is achieved is still debated.

This blog is mainly going to focus on the paper published in the journal of human kinetics in 2018 which looked at the effects of caffeine on physical parameters of sports performance, with one or two other factoids making an appearance along the way. Before we get into the nitty gritty I just want to point out some general things in relation to the usage of caffeine as an ergogenic aid (a substance that enhances sports performance). It is accepted that typical doses of caffeine to see a benefit in any sport, whether it be long steady state, field sports or repeat sprint efforts, is accepted as 3-6mg/kg, to put this into context, an 80kg man would have to consume the equivalent of a triple espresso to have any tangible benefit on his sporting performance (that’s a lot of coffee), caffeine takes about 45mins to peak in your blood stream if consumed as a drink like coffee, and as little as 15mins if consumed as caffeine gum or powder, which tend to be dosed in around 150-200mg per serving.

Consuming in excess of 500mg daily can lead to negative health consequences (this is about 6 coffees) whereas getting above 600mg daily may trigger a positive doping test. The sweet spot from a health perspective is not necessarily noted for caffeine itself, but for coffee, it is 3 a day for maximal protection against all cause mortality, liver fat buildup and dementia. Back to the task at hand.

You have likely done the maths in your head already and figured out how much caffeine you might need, and when you should be taking it, if you are satisfied and are not interested in the science, go forth and caffeinated yourself. If you are a habitual coffee drinker, and are wondering (as I am always asked this) if that will make caffeine supplementation less effective for you, the answer is no, caffeine supplementation at higher doses equally effects those who do and do not consume caffeine, with no difference in terms of enhancement of performance between those who drink the equivalent of one weak cup and those who drink 2-3 stronger cups daily. Now really, back to the research paper.

This study was a meta analysis, basically this means it pooled together a bunch of studies on the topic of caffeine supplementation, amalgamates all of the results to make broader conclusions, in most cases this is seen as the highest form of evidence, though it is not always ideal for nutrition based studies. 26 double blinded studies were included, with the most common dosage being 5-6mg/kg, which is the first caveat, as this is an uncommonly high ingestion rate, and for many it’s unrealistic from a tolerance point of view (and safety depending on weight), with the most common ingestion time being 60mins pre workout. The majority of the studies were done in cyclists and runners, with the exercise intensity ranging from 60-85% VO2max, or steady state aerobic range.

The findings of the study were as follows:

  1. No difference in effect between males & females
  2. Prior habitual caffeine consumption appeared not to be an issue in it’s effect
  3. Caffeine versus placebo saw significant increases in minute ventilation, blood glucose levels & blood lactate levels
  4. Caffeine versus placebo saw significantly lower ratings on the perceived effort scale
  5. There were no differences in heart rates or fat oxidation rates

The interesting thing that this study posits is that the subjects using caffeine were breathing heavier and at a higher rate per minute (minute ventilation) but were perceiving the exercise to be lower in it’s effort to complete it. There are still some unknowns about the mechanisms by which caffeine exerts it’s effect, what is thought to be a possibility is that adenosine (which is displaced by caffeine as it binds to adenosine receptors instead) can disrupt glucose clearance and glycolysis levels, having a clear impact on blood glucose levels. With blood glucose levels rising this would posit a logical basis to point to the cause of the increased lactate levels in the blood.

The final piece of the puzzle is that caffeine changes how sensitive chemoreceptors are to CO2 buildup in the bloodstream, prompting a higher minute ventilation rate versus placebo to lower this (you do not want high levels of CO2 in your blood), possibly accounting for the mismatch between minute ventilation rate, fat oxidation and blood glucose levels. This data is mechanistic in nature and has a number of hypothetical elements yet to be fully elucidated in the research.

Just for reference, a bottle of coke is about 40mg of caffeine, a cup tea is about 40-60mg, an espresso shot is about 80mg, a double is 160mg & an aeropress can be anywhere from 140-200mg depending on brew time and amount of grind used. Lighter roast coffees tend to give off high caffeine contents.

Brass tax – caffeine works, we just don’t completely know how yet.

Enjoy your cuppa.

E